Electrical and electronic equipment used in homes and offices require connections to power or signals which extend to outside sources. For example, many devices interface to external systems via such conductors as utility lines, telephone lines and remote antennas. Unfortunately, electronic equipment may also experience interference to normal operation or even catastrophic failure caused by disturbances and surges carried to the equipment via external conductors.
These disturbances are typically transient fluctuations, surges or spikes in voltage caused by the switching of large electrical loads sharing the power lines. Damaging disturbances may also be caused by irregularities in the power delivered by the utility company supplying the power. Occasionally, an extreme surge can be caused by a nearby lightning strike during a thunderstorm. In this case there is usually a dramatic rise in ground potential. One common protection scheme is to connect the equipment to the electrical grounding conductor. This practice subjects the equipment to this potentially damaging rising ground potential and renders conventional protection device ineffective.
The majority of these disturbances can be filtered out or trapped by using simple surge suppression technology or the use of uninterrupted power supplies (UPS). However, in the case of a lightning surge, conventional suppression devices typically do not provide a sufficient response time or have the energy dissipation capacity to adequately protect today""s sensitive electronic appliances and equipment.
There are over 20 million thunderstorms each year in the USA. It is also estimated that there are about 100 million lightning strikes each second. Some types of protection devices turn off electronic equipment when it is not in use. Unfortunately, the electronic equipment is still subject to damage because it is still connected to the external conductors that may carry damaging electrical disturbances.
There have been many different approaches to dealing with this problem. The most effective solution is to unplug or disconnect sensitive electronic devices, such as computers, VCRs and televisions when not in use for extended periods and particularly when a lightning storm is nearby. This however is usually unreliable since it is inconvenient and usually forgotten and in the case of modem refrigerators with electronic controls impractical.
U.S. Pat. No. 4,095,262 to St. Clair, for example is directed to protecting household appliances, such as a TV, for example, from surges caused by lightning, The apparatus includes a plurality of manually operated switches which may be connected for common operation. Accordingly, a user may manually switch the connections to isolate the equipment side conductors from the line and connect them to the chassis ground for protection. Unfortunately, the user must still remember to take the time to manually operate the switches prior to and after each use.
U.S. Pat. No. 6,104,582 to Cannon et al. is directed at transmitting a control signal that is generated by a weather service via telephone/modem lines or paging systems, to shut down computer equipment in the event that threatening weather conditions, are detected in the area of such equipment. This is a viable and sophisticated method, but one which requires an elaborate system and is limited to a certain coverage area.
It occurs to the inventor that, since a lightning strike is usually accompanied by thunder, and, since thunder can be heard three to four miles away from the actual site of the strike, it would be advantageous to detect the distinctive sound patterns of the thunder while potentially damaging lightning is still at a safe distance. This could be accomplished by utilizing available sound pattern recognition techniques. When the detected sounds are deemed to indicate a potentially threatening condition the connected equipment or appliances can be disconnected from the incoming conductors until the threat has passed.
U.S. Pat. No. 4,806,931 to Nelson is directed to compare sound patterns with previously stored patterns to identify certain sounds.
U.S. Pat. No. 6,038,118 to Eskildsen et al. is directed to compare the sound patterns of breaking glass with sound patterns stored in a processor to indicate an intrusion alarm when used in conjunction with an automatic security system.
In view of the foregoing background, it is therefore an object of the invention to provide and apparatus and associated method for protecting electrical and electronic equipment and appliances against potentially damaging disturbances carried to the equipment by external electrical conductors.
This and other objects, advantages and features of the invention are provided by a protection apparatus which in one embodiment is for the protection of a plurality of electrical equipment devices from electrical disturbances carried by external electrical conductors. The apparatus preferably comprises: a housing; means to connect the housing and internal circuitry to the external electrical conductors; a means of connecting external equipment to the housing for supply of electrical power and/or signals; a means of automatically or manually switching a plurality of devices from the normal operating state to the protected state; a multiple switching means to isolate the load side connected equipment from the line side conductors; the multiple switching means while in the protected state will connect all of the load side conductors to the chassis ground; one or more lights to indicate the present state of the apparatus.
The apparatus will also include a means of detecting sounds in the vicinity and comparing them to one or more sound patterns of thunder, which have been recorded or generated artificially and stored in a memory unit. If the detected sound pattern matches one or more of the stored patterns, thus indicating a thunder event and a potential threatening condition, the multiple switching means will transfer from the operating state to the protected state.
The apparatus may also have one or more timing devices, which will start a timing cycle upon confirmation of a thunder event. At the end of a specified time if the device has not detected any subsequent events the device will transfer the multiple switching device back to the normal operating state.
The apparatus may have one or more remote sensing units for use in instances when the equipment is in a location or a building where the outside sounds can not be picked up by the internal sensing unit.
The apparatus may have signal sending and receiving devices of the types used in X-10 units to facilitate remote activation of multiple switching devices, which are connected to a common electrical system.